1 /* $NetBSD: ip6_forward.c,v 1.65 2008/04/23 06:09:05 thorpej Exp $ */ 2 /* $KAME: ip6_forward.c,v 1.109 2002/09/11 08:10:17 sakane Exp $ */ 3 4 /* 5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the project nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __KERNEL_RCSID(0, "$NetBSD: ip6_forward.c,v 1.65 2008/04/23 06:09:05 thorpej Exp $"); 35 36 #include "opt_ipsec.h" 37 #include "opt_pfil_hooks.h" 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/malloc.h> 42 #include <sys/mbuf.h> 43 #include <sys/domain.h> 44 #include <sys/protosw.h> 45 #include <sys/socket.h> 46 #include <sys/errno.h> 47 #include <sys/time.h> 48 #include <sys/kernel.h> 49 #include <sys/syslog.h> 50 51 #include <net/if.h> 52 #include <net/route.h> 53 54 #include <netinet/in.h> 55 #include <netinet/in_var.h> 56 #include <netinet/ip_var.h> 57 #include <netinet/ip6.h> 58 #include <netinet6/ip6_var.h> 59 #include <netinet6/ip6_private.h> 60 #include <netinet6/scope6_var.h> 61 #include <netinet/icmp6.h> 62 #include <netinet6/nd6.h> 63 64 #ifdef IPSEC 65 #include <netinet6/ipsec.h> 66 #include <netinet6/ipsec_private.h> 67 #include <netkey/key.h> 68 #endif /* IPSEC */ 69 70 #ifdef FAST_IPSEC 71 #include <netipsec/ipsec.h> 72 #include <netipsec/ipsec6.h> 73 #include <netipsec/key.h> 74 #include <netipsec/xform.h> 75 #endif /* FAST_IPSEC */ 76 77 #ifdef PFIL_HOOKS 78 #include <net/pfil.h> 79 #endif 80 81 #include <net/net_osdep.h> 82 83 struct route ip6_forward_rt; 84 85 #ifdef PFIL_HOOKS 86 extern struct pfil_head inet6_pfil_hook; /* XXX */ 87 #endif 88 89 /* 90 * Forward a packet. If some error occurs return the sender 91 * an icmp packet. Note we can't always generate a meaningful 92 * icmp message because icmp doesn't have a large enough repertoire 93 * of codes and types. 94 * 95 * If not forwarding, just drop the packet. This could be confusing 96 * if ipforwarding was zero but some routing protocol was advancing 97 * us as a gateway to somewhere. However, we must let the routing 98 * protocol deal with that. 99 * 100 */ 101 102 void 103 ip6_forward(struct mbuf *m, int srcrt) 104 { 105 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 106 const struct sockaddr_in6 *dst; 107 struct rtentry *rt; 108 int error = 0, type = 0, code = 0; 109 struct mbuf *mcopy = NULL; 110 struct ifnet *origifp; /* maybe unnecessary */ 111 u_int32_t inzone, outzone; 112 struct in6_addr src_in6, dst_in6; 113 #ifdef IPSEC 114 struct secpolicy *sp = NULL; 115 int ipsecrt = 0; 116 #endif 117 #ifdef FAST_IPSEC 118 struct secpolicy *sp = NULL; 119 int needipsec = 0; 120 int s; 121 #endif 122 123 124 #ifdef IPSEC 125 /* 126 * Check AH/ESP integrity. 127 */ 128 /* 129 * Don't increment ip6s_cantforward because this is the check 130 * before forwarding packet actually. 131 */ 132 if (ipsec6_in_reject(m, NULL)) { 133 IPSEC6_STATINC(IPSEC_STAT_IN_POLVIO); 134 m_freem(m); 135 return; 136 } 137 #endif /* IPSEC */ 138 139 /* 140 * Do not forward packets to multicast destination (should be handled 141 * by ip6_mforward(). 142 * Do not forward packets with unspecified source. It was discussed 143 * in July 2000, on ipngwg mailing list. 144 */ 145 if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 || 146 IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) || 147 IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { 148 IP6_STATINC(IP6_STAT_CANTFORWARD); 149 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 150 if (ip6_log_time + ip6_log_interval < time_second) { 151 ip6_log_time = time_second; 152 log(LOG_DEBUG, 153 "cannot forward " 154 "from %s to %s nxt %d received on %s\n", 155 ip6_sprintf(&ip6->ip6_src), 156 ip6_sprintf(&ip6->ip6_dst), 157 ip6->ip6_nxt, 158 if_name(m->m_pkthdr.rcvif)); 159 } 160 m_freem(m); 161 return; 162 } 163 164 if (ip6->ip6_hlim <= IPV6_HLIMDEC) { 165 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 166 icmp6_error(m, ICMP6_TIME_EXCEEDED, 167 ICMP6_TIME_EXCEED_TRANSIT, 0); 168 return; 169 } 170 ip6->ip6_hlim -= IPV6_HLIMDEC; 171 172 /* 173 * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU - 174 * size of IPv6 + ICMPv6 headers) bytes of the packet in case 175 * we need to generate an ICMP6 message to the src. 176 * Thanks to M_EXT, in most cases copy will not occur. 177 * 178 * It is important to save it before IPsec processing as IPsec 179 * processing may modify the mbuf. 180 */ 181 mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN)); 182 183 #ifdef IPSEC 184 /* get a security policy for this packet */ 185 sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, 186 IP_FORWARDING, &error); 187 if (sp == NULL) { 188 IPSEC6_STATINC(IPSEC_STAT_OUT_INVAL); 189 IP6_STATINC(IP6_STAT_CANTFORWARD); 190 if (mcopy) { 191 #if 0 192 /* XXX: what icmp ? */ 193 #else 194 m_freem(mcopy); 195 #endif 196 } 197 m_freem(m); 198 return; 199 } 200 201 error = 0; 202 203 /* check policy */ 204 switch (sp->policy) { 205 case IPSEC_POLICY_DISCARD: 206 /* 207 * This packet is just discarded. 208 */ 209 IPSEC6_STATINC(IPSEC_STAT_OUT_POLVIO); 210 IP6_STATINC(IP6_STAT_CANTFORWARD); 211 key_freesp(sp); 212 if (mcopy) { 213 #if 0 214 /* XXX: what icmp ? */ 215 #else 216 m_freem(mcopy); 217 #endif 218 } 219 m_freem(m); 220 return; 221 222 case IPSEC_POLICY_BYPASS: 223 case IPSEC_POLICY_NONE: 224 /* no need to do IPsec. */ 225 key_freesp(sp); 226 goto skip_ipsec; 227 228 case IPSEC_POLICY_IPSEC: 229 if (sp->req == NULL) { 230 /* XXX should be panic ? */ 231 printf("ip6_forward: No IPsec request specified.\n"); 232 IP6_STATINC(IP6_STAT_CANTFORWARD); 233 key_freesp(sp); 234 if (mcopy) { 235 #if 0 236 /* XXX: what icmp ? */ 237 #else 238 m_freem(mcopy); 239 #endif 240 } 241 m_freem(m); 242 return; 243 } 244 /* do IPsec */ 245 break; 246 247 case IPSEC_POLICY_ENTRUST: 248 default: 249 /* should be panic ?? */ 250 printf("ip6_forward: Invalid policy found. %d\n", sp->policy); 251 key_freesp(sp); 252 goto skip_ipsec; 253 } 254 255 { 256 struct ipsecrequest *isr = NULL; 257 struct ipsec_output_state state; 258 259 /* 260 * when the kernel forwards a packet, it is not proper to apply 261 * IPsec transport mode to the packet is not proper. this check 262 * avoid from this. 263 * at present, if there is even a transport mode SA request in the 264 * security policy, the kernel does not apply IPsec to the packet. 265 * this check is not enough because the following case is valid. 266 * ipsec esp/tunnel/xxx-xxx/require esp/transport//require; 267 */ 268 for (isr = sp->req; isr; isr = isr->next) { 269 if (isr->saidx.mode == IPSEC_MODE_ANY) 270 goto doipsectunnel; 271 if (isr->saidx.mode == IPSEC_MODE_TUNNEL) 272 goto doipsectunnel; 273 } 274 275 /* 276 * if there's no need for tunnel mode IPsec, skip. 277 */ 278 if (!isr) 279 goto skip_ipsec; 280 281 doipsectunnel: 282 /* 283 * All the extension headers will become inaccessible 284 * (since they can be encrypted). 285 * Don't panic, we need no more updates to extension headers 286 * on inner IPv6 packet (since they are now encapsulated). 287 * 288 * IPv6 [ESP|AH] IPv6 [extension headers] payload 289 */ 290 bzero(&state, sizeof(state)); 291 state.m = m; 292 state.ro = NULL; /* update at ipsec6_output_tunnel() */ 293 state.dst = NULL; /* update at ipsec6_output_tunnel() */ 294 295 error = ipsec6_output_tunnel(&state, sp, 0); 296 297 m = state.m; 298 key_freesp(sp); 299 300 if (error) { 301 /* mbuf is already reclaimed in ipsec6_output_tunnel. */ 302 switch (error) { 303 case EHOSTUNREACH: 304 case ENETUNREACH: 305 case EMSGSIZE: 306 case ENOBUFS: 307 case ENOMEM: 308 break; 309 default: 310 printf("ip6_forward (ipsec): error code %d\n", error); 311 /* FALLTHROUGH */ 312 case ENOENT: 313 /* don't show these error codes to the user */ 314 break; 315 } 316 IP6_STATINC(IP6_STAT_CANTFORWARD); 317 if (mcopy) { 318 #if 0 319 /* XXX: what icmp ? */ 320 #else 321 m_freem(mcopy); 322 #endif 323 } 324 m_freem(m); 325 return; 326 } 327 328 if (ip6 != mtod(m, struct ip6_hdr *)) { 329 /* 330 * now tunnel mode headers are added. we are originating 331 * packet instead of forwarding the packet. 332 */ 333 ip6_output(m, NULL, NULL, IPV6_FORWARDING/*XXX*/, NULL, NULL, 334 NULL); 335 goto freecopy; 336 } 337 338 /* adjust pointer */ 339 rt = state.ro ? rtcache_validate(state.ro) : NULL; 340 dst = (const struct sockaddr_in6 *)state.dst; 341 if (dst != NULL && rt != NULL) { 342 ipsecrt = 1; 343 goto skip_routing; 344 } 345 } 346 skip_ipsec: 347 #endif /* IPSEC */ 348 #ifdef FAST_IPSEC 349 /* Check the security policy (SP) for the packet */ 350 351 sp = ipsec6_check_policy(m,NULL,0,&needipsec,&error); 352 if (error != 0) { 353 /* 354 * Hack: -EINVAL is used to signal that a packet 355 * should be silently discarded. This is typically 356 * because we asked key management for an SA and 357 * it was delayed (e.g. kicked up to IKE). 358 */ 359 if (error == -EINVAL) 360 error = 0; 361 goto freecopy; 362 } 363 #endif /* FAST_IPSEC */ 364 365 if (srcrt) { 366 union { 367 struct sockaddr dst; 368 struct sockaddr_in6 dst6; 369 } u; 370 371 sockaddr_in6_init(&u.dst6, &ip6->ip6_dst, 0, 0, 0); 372 if ((rt = rtcache_lookup(&ip6_forward_rt, &u.dst)) == NULL) { 373 IP6_STATINC(IP6_STAT_NOROUTE); 374 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_noroute) */ 375 if (mcopy) { 376 icmp6_error(mcopy, ICMP6_DST_UNREACH, 377 ICMP6_DST_UNREACH_NOROUTE, 0); 378 } 379 m_freem(m); 380 return; 381 } 382 } else if ((rt = rtcache_validate(&ip6_forward_rt)) == NULL && 383 (rt = rtcache_update(&ip6_forward_rt, 1)) == NULL) { 384 /* 385 * rtcache_getdst(ip6_forward_rt)->sin6_addr was equal to 386 * ip6->ip6_dst 387 */ 388 IP6_STATINC(IP6_STAT_NOROUTE); 389 /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_noroute) */ 390 if (mcopy) { 391 icmp6_error(mcopy, ICMP6_DST_UNREACH, 392 ICMP6_DST_UNREACH_NOROUTE, 0); 393 } 394 m_freem(m); 395 return; 396 } 397 dst = satocsin6(rtcache_getdst(&ip6_forward_rt)); 398 #ifdef IPSEC 399 skip_routing:; 400 #endif /* IPSEC */ 401 402 /* 403 * Source scope check: if a packet can't be delivered to its 404 * destination for the reason that the destination is beyond the scope 405 * of the source address, discard the packet and return an icmp6 406 * destination unreachable error with Code 2 (beyond scope of source 407 * address). We use a local copy of ip6_src, since in6_setscope() 408 * will possibly modify its first argument. 409 * [draft-ietf-ipngwg-icmp-v3-07, Section 3.1] 410 */ 411 src_in6 = ip6->ip6_src; 412 if (in6_setscope(&src_in6, rt->rt_ifp, &outzone)) { 413 /* XXX: this should not happen */ 414 uint64_t *ip6s = IP6_STAT_GETREF(); 415 ip6s[IP6_STAT_CANTFORWARD]++; 416 ip6s[IP6_STAT_BADSCOPE]++; 417 IP6_STAT_PUTREF(); 418 m_freem(m); 419 return; 420 } 421 if (in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone)) { 422 uint64_t *ip6s = IP6_STAT_GETREF(); 423 ip6s[IP6_STAT_CANTFORWARD]++; 424 ip6s[IP6_STAT_BADSCOPE]++; 425 IP6_STAT_PUTREF(); 426 m_freem(m); 427 return; 428 } 429 if (inzone != outzone 430 #ifdef IPSEC 431 && !ipsecrt 432 #endif 433 ) { 434 uint64_t *ip6s = IP6_STAT_GETREF(); 435 ip6s[IP6_STAT_CANTFORWARD]++; 436 ip6s[IP6_STAT_BADSCOPE]++; 437 IP6_STAT_PUTREF(); 438 in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard); 439 440 if (ip6_log_time + ip6_log_interval < time_second) { 441 ip6_log_time = time_second; 442 log(LOG_DEBUG, 443 "cannot forward " 444 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 445 ip6_sprintf(&ip6->ip6_src), 446 ip6_sprintf(&ip6->ip6_dst), 447 ip6->ip6_nxt, 448 if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp)); 449 } 450 if (mcopy) 451 icmp6_error(mcopy, ICMP6_DST_UNREACH, 452 ICMP6_DST_UNREACH_BEYONDSCOPE, 0); 453 m_freem(m); 454 return; 455 } 456 #ifdef FAST_IPSEC 457 /* 458 * If we need to encapsulate the packet, do it here 459 * ipsec6_proces_packet will send the packet using ip6_output 460 */ 461 if (needipsec) { 462 s = splsoftnet(); 463 error = ipsec6_process_packet(m,sp->req); 464 splx(s); 465 if (mcopy) 466 goto freecopy; 467 } 468 #endif 469 470 471 472 /* 473 * Destination scope check: if a packet is going to break the scope 474 * zone of packet's destination address, discard it. This case should 475 * usually be prevented by appropriately-configured routing table, but 476 * we need an explicit check because we may mistakenly forward the 477 * packet to a different zone by (e.g.) a default route. 478 */ 479 dst_in6 = ip6->ip6_dst; 480 if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 || 481 in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 || 482 inzone != outzone) { 483 uint64_t *ip6s = IP6_STAT_GETREF(); 484 ip6s[IP6_STAT_CANTFORWARD]++; 485 ip6s[IP6_STAT_BADSCOPE]++; 486 IP6_STAT_PUTREF(); 487 m_freem(m); 488 return; 489 } 490 491 if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) { 492 in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig); 493 if (mcopy) { 494 u_long mtu; 495 #ifdef IPSEC 496 struct secpolicy *xsp; 497 int ipsecerror; 498 size_t ipsechdrsiz; 499 #endif 500 501 mtu = IN6_LINKMTU(rt->rt_ifp); 502 #ifdef IPSEC 503 /* 504 * When we do IPsec tunnel ingress, we need to play 505 * with the link value (decrement IPsec header size 506 * from mtu value). The code is much simpler than v4 507 * case, as we have the outgoing interface for 508 * encapsulated packet as "rt->rt_ifp". 509 */ 510 xsp = ipsec6_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND, 511 IP_FORWARDING, &ipsecerror); 512 if (xsp) { 513 ipsechdrsiz = ipsec6_hdrsiz(mcopy, 514 IPSEC_DIR_OUTBOUND, NULL); 515 if (ipsechdrsiz < mtu) 516 mtu -= ipsechdrsiz; 517 } 518 519 /* 520 * if mtu becomes less than minimum MTU, 521 * tell minimum MTU (and I'll need to fragment it). 522 */ 523 if (mtu < IPV6_MMTU) 524 mtu = IPV6_MMTU; 525 #endif 526 icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu); 527 } 528 m_freem(m); 529 return; 530 } 531 532 if (rt->rt_flags & RTF_GATEWAY) 533 dst = (struct sockaddr_in6 *)rt->rt_gateway; 534 535 /* 536 * If we are to forward the packet using the same interface 537 * as one we got the packet from, perhaps we should send a redirect 538 * to sender to shortcut a hop. 539 * Only send redirect if source is sending directly to us, 540 * and if packet was not source routed (or has any options). 541 * Also, don't send redirect if forwarding using a route 542 * modified by a redirect. 543 */ 544 if (rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && ip6_sendredirects && 545 #ifdef IPSEC 546 !ipsecrt && 547 #endif 548 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) { 549 if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) && 550 nd6_is_addr_neighbor( 551 satocsin6(rtcache_getdst(&ip6_forward_rt)), 552 rt->rt_ifp)) { 553 /* 554 * If the incoming interface is equal to the outgoing 555 * one, the link attached to the interface is 556 * point-to-point, and the IPv6 destination is 557 * regarded as on-link on the link, then it will be 558 * highly probable that the destination address does 559 * not exist on the link and that the packet is going 560 * to loop. Thus, we immediately drop the packet and 561 * send an ICMPv6 error message. 562 * For other routing loops, we dare to let the packet 563 * go to the loop, so that a remote diagnosing host 564 * can detect the loop by traceroute. 565 * type/code is based on suggestion by Rich Draves. 566 * not sure if it is the best pick. 567 */ 568 icmp6_error(mcopy, ICMP6_DST_UNREACH, 569 ICMP6_DST_UNREACH_ADDR, 0); 570 m_freem(m); 571 return; 572 } 573 type = ND_REDIRECT; 574 } 575 576 /* 577 * Fake scoped addresses. Note that even link-local source or 578 * destinaion can appear, if the originating node just sends the 579 * packet to us (without address resolution for the destination). 580 * Since both icmp6_error and icmp6_redirect_output fill the embedded 581 * link identifiers, we can do this stuff after making a copy for 582 * returning an error. 583 */ 584 if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) { 585 /* 586 * See corresponding comments in ip6_output. 587 * XXX: but is it possible that ip6_forward() sends a packet 588 * to a loopback interface? I don't think so, and thus 589 * I bark here. (jinmei@kame.net) 590 * XXX: it is common to route invalid packets to loopback. 591 * also, the codepath will be visited on use of ::1 in 592 * rthdr. (itojun) 593 */ 594 #if 1 595 if (0) 596 #else 597 if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0) 598 #endif 599 { 600 printf("ip6_forward: outgoing interface is loopback. " 601 "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 602 ip6_sprintf(&ip6->ip6_src), 603 ip6_sprintf(&ip6->ip6_dst), 604 ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif), 605 if_name(rt->rt_ifp)); 606 } 607 608 /* we can just use rcvif in forwarding. */ 609 origifp = m->m_pkthdr.rcvif; 610 } 611 else 612 origifp = rt->rt_ifp; 613 /* 614 * clear embedded scope identifiers if necessary. 615 * in6_clearscope will touch the addresses only when necessary. 616 */ 617 in6_clearscope(&ip6->ip6_src); 618 in6_clearscope(&ip6->ip6_dst); 619 620 #ifdef PFIL_HOOKS 621 /* 622 * Run through list of hooks for output packets. 623 */ 624 if ((error = pfil_run_hooks(&inet6_pfil_hook, &m, rt->rt_ifp, 625 PFIL_OUT)) != 0) 626 goto senderr; 627 if (m == NULL) 628 goto freecopy; 629 ip6 = mtod(m, struct ip6_hdr *); 630 #endif /* PFIL_HOOKS */ 631 632 error = nd6_output(rt->rt_ifp, origifp, m, dst, rt); 633 if (error) { 634 in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard); 635 IP6_STATINC(IP6_STAT_CANTFORWARD); 636 } else { 637 IP6_STATINC(IP6_STAT_FORWARD); 638 in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward); 639 if (type) 640 IP6_STATINC(IP6_STAT_REDIRECTSENT); 641 else { 642 #ifdef GATEWAY 643 if (m->m_flags & M_CANFASTFWD) 644 ip6flow_create(&ip6_forward_rt, m); 645 #endif 646 if (mcopy) 647 goto freecopy; 648 } 649 } 650 651 #ifdef PFIL_HOOKS 652 senderr: 653 #endif 654 if (mcopy == NULL) 655 return; 656 switch (error) { 657 case 0: 658 if (type == ND_REDIRECT) { 659 icmp6_redirect_output(mcopy, rt); 660 return; 661 } 662 goto freecopy; 663 664 case EMSGSIZE: 665 /* xxx MTU is constant in PPP? */ 666 goto freecopy; 667 668 case ENOBUFS: 669 /* Tell source to slow down like source quench in IP? */ 670 goto freecopy; 671 672 case ENETUNREACH: /* shouldn't happen, checked above */ 673 case EHOSTUNREACH: 674 case ENETDOWN: 675 case EHOSTDOWN: 676 default: 677 type = ICMP6_DST_UNREACH; 678 code = ICMP6_DST_UNREACH_ADDR; 679 break; 680 } 681 icmp6_error(mcopy, type, code, 0); 682 return; 683 684 freecopy: 685 m_freem(mcopy); 686 return; 687 } 688